Comparison of plethysmographic methods with pulsed Döppler blood flowmetry.

Hand blood flow was measured at rest, with local warming, and with local cooling. Three methods were simultaneously used: water plethysmography (WP), mercury-in-rubber strain gauge plethysmography (SG), and pulsed Döppler flowmetry (D). Of these, water plethysmography is the most sensitive and accurate; strain gauge plethysmography is simpler but less accurate; and pulsed Döppler flowmetry precisely measures instantaneous arterial blood flow without venous occlusion.